Regulating system



June 5, 1928.

R. M. cARoTHERs REGULATING SYSTEM Ffiied June 24, 1925 Patented June 5, 1928.

"UNITED mus v 1,672,674 PATENT OFFICE.

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My invention relates to re lating and more particularly to vo tage re latmg systems in which regulators of the vibratory type are employed to efiect the desired regulation. i

In regulating systems in which regulators of the well known Tirrill type are used, the

floating main contacts usually operate to effect the operation of a relay having contacts which periodically short-circuit or insert a resistor in the field circuit of the regulated machine or the field circuit of an exciter therefor. In order to decrease the duty .imposed upon a single pa1r of relay contacts, when a relatively hi h field excitation is required, a plurality o rela s operating a plurality of series connects contacts have been arranged to operate simultaneously across the entire field resistor so that each single pair of contacts operates across a different portion of the resistor. To relieve still further the duty of each single pair of contacts in the series connected arrangement, a second set of contacts have I been arranged in parallel with the first mentioned contacts so that there are two sets of contacts for a given portion of the resistor. In the arrangements employi a plurality of relays it is difiicult to adjust t e relays and to maintain the adjustment so that the contacts are opened simultaneously. In case one pair of contacts opens prematurel the normally designed duty, on the set 0 contacts operated in parallel with the contacts which have opened, will be doubled, and

sparking and pitting of the contacts willoccur, thereby efiecting the operation of the regulator.

An object of my invention is toprovide anarrangement of connections for a resistor controlled by a plurality of series connected contacts in systems of regulation which w-1ll reduce the possibility of doubling the normally designed duty of a single pair of con- 6 tacts; and thereby reduce or eliminate I sparking and pittin of the contacts.

My invention w'l be'better understood from the following description taken in connection with the. accompanyin drawing in which the single figure is a iagrammatic illustration'of a regulating system embodying 'y invention, and its scope will be pointed out in the appended claims.

*Itferrin to the drawing,'1 represents a 6 generator evolta'ge of which is to be mainsystems 12, 13, 14, 15, 16, 17 and 18 whic tained constant. As shown generator 1 is represented diagrammatically as an alternator which is connected to an alternating current circuit 2, but it will be evident that my invent-ion is not limited to any particular t of generator. The generator 1 is rovi ed with a field winding 3 which is excited by a suitable source of current shown as an exciter 4. The exciter 4 is provided with a shunt field windin '5 and a resistor 6 in series therewith w ich is arranged to be short-circuited by means of vibrator regulator 7 such as a regplator of the Tirrill type. The regulator? s owni'sof the well known construction comprising two coo erating contacts 8 and 9 which are actuate respectively by a direct current magnet 10 connected across the exciter 4 and an alternatmg current magnet 11 connected across the alternating current circuit 2. The contacts 8 and 9 are connected in series relation with the energizing circuit of a plurality of relays are connected to be simultaneously energized from the armature of exciter 4. These relays in the order enumerated are provided respectively with operating coils 19, 20, 21, 22, 23,

24 and 25, and contacts 26, 27, 28, 29, 30, 31 and 32. The relays are normally arranged to operate simultaneously so that theresistor 6 is periodically short-circuited when contacts 8 and 9 are in engagement.

For convenience of explanation, resistor 6 is indicated as comprising equal sections of resistances desi ated as a, b, c, d, e, and f. Contacts 26 w en closed are arranged to short-circuit section a while contacts 32 are arranged to short-circuit sections 04- b. In like manner contacts 29 when closed arearranged to short-"circuit section-f while contacts 30 are arranged to short-circuit section e+f. Each pair-of the remaining contacts individually short-circuit two sectlons while a single section of each set of double sections is also controlled by another pair of contacts. Thus, contacts 27 are arranged to shortcircuit sections 6+0, contacts 31 are arranged to short-circuit sections 0+d, and contacts 28 are arranged to shortcircuitsections (1+0. It will thus be observed that eachset of contacts controls a difierent portion of the field resistor, but they are so arranged that if one contact is rendered inoperative another contact will not be during each vibration.

The operation of the regulator shown is well known in the art, and it is believed that a brief description thereof will be sufficient. .It is evident that the exciter voltage is controlled by the rapid opening and closing of contacts 8 and 9 and that the exciter voltage depends upon the length of time the contacts remain in engagement Upon the engagement of contacts 8 and 9, an energizing circuit is completed across exciter 4 for the relays L9 to 25 inclusive so that the contacts 26 to 32 inclusive are closed. Furthermore, it is evident that the length of time the contacts 8 and 9 remain in engagement with each other depends upon the load connected to the alternating current circuit 2. At any constant load the contact 9 remains stationary and the contact 8 vibrates so that the regulator acts as a direct current regulator to maintain the proper exciter voltage. When the load on the generator 1 increases,

the voltage of the generator is decreased so that contact 9 moves towards contact 8. Consequently the contacts 8 and 9 are in engagement a greater portion of the time during each vibration of contact 8. Therefore, the resistor 6 is short-circuited more of the time which in turn causes the exciter voltage to increase. When the exciter voltage reaches a value corresponding to that required to give normal alternating voltage under the new conditions, the alternating current magnet 11 remains stationary in its new position and the direct current magnet 10 then operates to maintain the exciter voltage at this higher value in order to hold the desired alternating voltage.

In the above general outline of the operation of the regulator, it was assumed that the relays controlling the resistor 6 opened or closed simultaneously. Since the main contacts 8 and 9 make roughly from 400 to 900 oscillations per minute, it is, of course,

evident that the adjustment of these relays for simultaneous operation is diflicult to maintain. Should one relay open prematurely in the arrangement in which two contacts operate in parallel across the same section of the resistor, the duty is doubled on the contact which opens with the remaining contacts. Now, in the present arrangement, for purposes of explanation, it will be assumed that contacts 32 which are arranged to short-circuit sections a+b, open prematurely. Under these conditions contacts 26 will open the circuit across a single section a, -while contacts 27 will open the circuit across sections b+c. However, this does not necessitate the operation of contacts 27 across 6+0 unaided since contacts 31 operate to open the circuit across c+d, thereby providing two contacts which and 29 across sections a and 7 respectively.

While I have shown and described a particular embodiment of my invention, it will be obvious to thoseskilled in the art that changes and modifications may be made without departing from my invention, and

I, therefore, aim in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is 2-- 1. In a regulating system, an electric circuit, an impedance for efiecting a change in an electrical characteristic of said circuit, a. plurality of groups of series connected contacts associated with the same part of said impedance, each of said contacts being arranged to control a difierent portion of said part of said impedance, and means for opening and closing said contacts for con-- trolling the effective value of said imped- 'means for opening and closing said con-- tacts for controlling the effective value of said resistor.

3. In a regulating system, an electric cir- I cuit, a resistor for eflecting a change in an electrical characteristic of said circuit, a plurality of groups of series connected contacts associated with said resistor, each pair of contacts of one group of said contacts being arranged to be connected across portions of said resistor and each pair of the contacts of another group of said contacts being connected to points between the connections of said first group, and means for opemng and closing said contacts for controlling the efiective value of said resistor. I

4. In a regulating system, a dynamo-else: tric machine, a resistor for controlling the excitation of said. dynamo-electric machine,

a plurality of groups of series connected con- 1;, tacts associated with the same part of said resistor, each of said contacts being consaid resistor, and electro-magnetic devices responsive to an electrical characteristic of said dynamo-electric machine for controlling the opening and closing of said series connected contacts. I

5. In a regulating system, the combination of a pair of cooperating contacts arranged to effect by their engagement and disengagement the desired regulation, means for actuating one of said contacts in accordance with the condition being regulated, an electromagnet for operating the other of said contacts, a source of excitation having an excitation circuit connected to said electromagnet, an impedance device in the excitation circuit of said source of-excitation, a plurality of groups of series connected contacts associated with the same part of said impedance device, each of said contacts being arranged to control a diflt'erent section of said part of said impedance device, and a plurality of electro-magnetic devices connectedin a circuit across said source of excitation and operative in response to the engagement and disengagement of said' cooperating. contacts for controlling said series connected contacts. r

6. The combination of a dynamo-electric machine, an exciter therefor, a regulator for said machine having cooperating contacts and operating coilsjor controlling the movement of said cooperating contacts, one of said operating coils being connected to beresponsive to an electrical characteristic of said dynamo-electric machine and the other. of

said coils being connected to be responsive to an electrical characteristic of said exciter,

a resistor for varying the excitation of' said exciter, a plurality of groups of series con-- nected contacts associated with the same part of said resistor, each of said contacts being connected to-control a different section of said part of said resistor, and a plurality of relays, one for each of said contacts, operative in response to the engagement and disenga mentof said cooperating contacts for effecting the closing and opening of. said series: connected contacts;

7. The combination of a dynamo-electric machine, an exciter therefor, .a regulator for said machine having cooperating contacts and operating coils for controlling the movement of said cooperating contacts, one of said operating coils being connected to'be responsive to an electrical characteristic of said dynamo-electric machine and the other of said coils being connected to be responsive to an electrical characteristic of said exciter, a resistor for varying the excitation of said exciter, a plurality of groups of series connected contacts associated with said resistor, each pair of the contacts of one group of said contacts being arranged to be connected across portions of said resistor and each pair of the contacts of another group being connected to points intermediate the connecative in responseto the engagement and disengagement of said cooperating contacts for effecting the closing and opening of said series. connected contacts.

- 8. In a regulating system, an electric circuit, a resistor associated with said electric circuit for effecting a change in an electrical characteristic of said circuit, and a plurality of means arranged normally for operation simultaneously for "changing the efiective value of said. resistor comprising a plurality of relay's' 'for'operating a plurality of groups of series connected contacts adapted to be connected across the same part of said resistor; each pair of said contacts being connected to control a different section of said part of said resistor for reducing sparking and pitting of the contacts upon premature operation of any one pair of said contacts.

In witness whereof, I have hereunto set my hand this 23d day of June, 1926.

ROBERT M. cano'rnnns. 

